WPF拦截模式窗口外的单击

Is it possible to check when the user has clicked outside a modal window? I'd like to somehow circumvent the modal logic because if the window isn't displayed as modal, it will not be shown on top of the active window, and, for now, this is the only way to display it correctly. I haven't found a proper way to do just that (since the "deactivate" event will no longer be triggered..)Is it possible to check when the user has click